Question: Correct use of "Broken Chains" about promises HOT 2 CLOSED

Hi Richard,

The code looks good. I'd only call out the issue if you possibly get another login invocation before the previous request had a chance to complete. May like to store the promise in an optional var and reject it on another login attempt. Something like the following:

class LoginService {
  // ...
  var loginPromise: Promise<String>?

  func login(username: String = "", password: String = "") -> Promise<String> {
    assert(Thread.isMainThread)
    loginPromise?.reject(...)
    auth?.token = ""
    weak var weakSelf = self
    let promise = self.client.request(
      API.authenticate(username: username, password: password)
    ).then { token in
      weakSelf?.auth?.token = token
      weakSelf?.loginPromise = nil
    }
    loginPromise = promise
    return promise
  }
  // ...
}

May also consider returning loginPromise if it's not nil and the username matches the previous invocation. So, everything depends on your use cases.

from promises.

Thanks for clarifying the issue with another invocation. Practically, it's impossible, as the UI locks immediately before the login code is invoked. Other than this, I'm happy to hear that I use the library properly.

from promises.